1. Field of the Invention
The present invention relates to a sheet folding apparatus comprising a sheet transport system, adjustable folding members arranged to bend and fold a sheet fed by the transport system, and a control system arranged to adjust the folding members to set positions in accordance with information on sheet properties.
The present invention further relates to a sheet folding method and to a printing system including the sheet folding apparatus.
2. Background of the Invention
U.S. Pat. No. 4,518,380 describes a sheet folding apparatus, wherein a first folding member is formed by a stop member arranged in a feed path of the sheets. When a leading edge of a sheet is stopped by the stop member while the trailing part of the sheet is still fed by the transport system, the sheet will be bent and will form a loop. A second folding member is formed by a pair of rollers forming a nip that will capture and fold the loop formed in the sheet. The position of the stop member will determine the folding length of the sheet and can be adjusted manually in accordance with the desired folding length.
U.S. Pat. No. 5,242,364 discloses a sheet folding apparatus comprising a plurality of folding stations, each including a stop member and a roller pair. The transport system includes deflection members for controlling the path of the sheets through the folding stations, so that different folding patterns may be programmed. The control system includes actuators for actively adjusting the positions of the stop members in accordance with the desired folding lengths. Further, the control system includes actuators for adjusting the widths of the gaps formed at the nip of each roller pair. The width of the gap is automatically adjusted in accordance with the thickness of the sheets and the number of layers of the folded sheet that have to pass through the respective nip.